Display checkboxes from frontend form

I have frontend form for participants in the competition. There is dropdown list of CPT categories in the form from which participants choose one category.
I need help to display choosen category in admin post edit page.

This is how I add post:

    $post_id = wp_insert_post(array (
        'post_title' => $company,
        'post_status'   => 'draft',
        'post_type'     => 'member',
    ));
    if ($post_id) {
        update_post_meta($post_id, 'site_name', $membersite);
        update_post_meta($post_id, 'site_url', $membersite);
        update_post_meta($post_id, 'nomination', $nomination);
    }

I can successfuly update site_name and site_url fields (text in input field) but nothing uppears in categories which display as checkbox list.

Any help is appreciated.